PLANT/CROP-BASED RENEWABLE RESOURCES 2020 - NREL
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PLANT/CROP-BASED
RENEWABLE RESOURCES 2020
A V I S I O N TO E N H A N C E U. S . E C O N O M I C S E C U R I T Y
T H R O U G H R E N E WA B L E P L A N T / C R O P - B A S E D R E S O U R C E U S EAbout This Vision This strategic vision for the plant/crop-based renewables industry was developed by the broad U.S. agricultural, forestry, and chemical communities, with contributions from a wide range of individuals. A uniquely diverse set of American companies, nonprofit groups, trade associations, and academic institutions have come together for the first time to produce a shared vision of the future for this emerging industry. The National Corn Growers Association initiated this effort through a strategic visioning workshop held in St. Louis in December, 1996. The goal of this workshop was to start crafting an industry vision that would lead us into an era where plant/crop-based renewables could serve as comple- mentary resources to conventional feedstocks to meet our ever-growing need for chemicals, materials, and other products. This vision document broadly outlines the poten- tial reaches of this home-grown industry into the core man- ufacturing capabilities of this nation. This document is also an invitation to all readers to participate in developing the technology plans that will make the vision a reality.
PLANT/CROP-BASED RENEWABLE RESOURCES 2020
TABLE OF C ONTENTS
2 E XECUTIVE S UMMARY
4 I NTRODUCTION
What Are Plant/Crop-based Resources?
The Hydrocarbon Economy
8 T HE V ISION FOR P LANT /C ROP - BASED R ENEWABLES
IN 2020
9 P LANT /C ROP - BASED R ESOURCES AS F EEDSTOCKS :
C URRENT S TATUS
Situation Analysis
Utility
Supply and Quality
Cost of Plant/Crop-based Raw Materials Today
13 P LANT /C ROP - BASED R ESOURCES AS F EEDSTOCKS :
L OOKING A HEAD
A Matrix for Analysis of Future Developments
Segment Potentials
Waste Streams and By-products
Existing Crop Parts
Dedicated Crops
Modified Genetics
21 T HE P OTENTIAL I MPACT OF B IOTECHNOLOGY
23 W ORKING A PPROACH
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
1E XECUTIVE S UMMARY
lant/crop-based resources are defined as source material derived from a
P wide range of biological plant systems and processing streams in the
food, feed, and fiber industries. An inherent assumption is that these resources
are renewable over a short time frame, through use of annual crops, perenni-
als, and short-rotation woody species. The U.S. has significant plant/crop-
based resources, including forestry, rangeland, and a highly productive
agricultural system. In the past 50 years, these resources have been largely
focused toward food, feed and fiber production. Use of plant/crop resources
for energy, or as basic building blocks for industrial production, has been lim-
ited because of a poor fit with the hydrocarbon processing system that has
been successfully developed to utilize fossil fuels.
Sustained economic growth depends on having a secure supply of raw mater-
ial inputs. With rapid world growth and continuing changes in consumer
demands, there is a need to find additional, and preferably renewable,
resources for industrial production and energy needs.
Figure 1. This matrix creates
a structure for evaluating The vision is to provide continued economic growth, healthy standards of living,
opportunities and priority areas and strong national security through the development of plant/crop-based renew-
for research and development. able resources that are a viable alternative to the current dependence on non-
renewable, diminishing fossil fuels.
Novel
molecules
The concepts inherent in this vision do not
imply that hydrocarbon processing systems
Processing systems
Bio-
processes must be thrown out. Rather, the need is to
explore the developing “technology front” for
Modified
chemistry opportunities to:
a) utilize plant/crop-based inputs in modi-
Current
chemistry
fied processing systems,
b) develop modified plant/crop production
Year systems to provide desirable feed
2020 stocks, and
Waste & c) integrate these approaches to create
by-products optimized systems that generate a new
economic platform based on the utiliza-
Existing Technology tion of plant/crop-derived inputs.
Plant input
crop parts
front today
Dedicated
crops
Modified
genetics
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
2While a vision looks forward and points to future potential, it is also recognized
that change must start today. Change itself is often continuous with break-
throughs occurring at infrequent intervals. Ideally, actions and goals in support
of a visionary direction should allow for incremental and breakthrough types of
change. Successful progress will be achieved by integrated, multidisciplinary
research in a phased approach.
Many of the current limi-
State & rural
development tations to the use of
plant-based materials
University &
basic research Multi- arise from attempts
functional to fit carbohy-
market- Modified drate chem-
Industry R&D Opportunistic use Modified
driven processing & istry into a
in current systems processing
research modified crops
hydrocarbon
Grower groups programs
chemistry situa-
tion. In many cases,
Federal
government Today Near term Longer term major sources of plant
materials are not
even geographically suited to the locations of petrochemical processing facili-
Figure 2. Successful progress will
be achieved by integrated, multi- ties. The use of plant/crop-based resources requires the development of
disciplinary research in phases. concepts around “alternative processing” rather than just “alternative sources”
for existing processes.
In the shorter term, modified processes will allow economic use of plant/crop-
based resources, while longer-term opportunities exist via the application of
recent biotechnology advances.
“It is not the strongest Plant/crop-based renewable resources are a strategic option to meet the grow-
of the species that survive, ing need for industrial building blocks, and to maintain the leadership position
nor the most intelligent, of the U.S. into the next century. There will be economic, environmental and
societal advantages from the development of this resource base. The opportu-
but the one most responsive
nity is clear. However, it requires forward-thinking vision, integration of stake-
to change.”
holders, investment in new approaches, and coordination of research to
—Charles Darwin generate a secure future.
This document outlines a visionary direction and states the case for using
plant/crop-based renewable resources as a viable strategic option for sus-
tained industrial growth. While directional targets and examples are provided it
is recognized that there is a need to have the various stakeholders participate
in a coordinated effort to identify and quantify appropriate goals, and to initiate
specific projects in support of the vision.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
3I NTRODUCTION
Imagine how the world has changed over the past 100 years: that’s the magnitude
of change we can expect in the next 20 to 25 years. Technological change, social
structure change, human population change. It can be a terrifying picture or it
Figure 3. Production of the can be an exciting vision.
world's biomass (plant-based)
materials compared to the he pessimistic viewpoint is that world resources are insufficient to maintain
proportion utilized.
T the current exponential expansion. With no further developments to exist-
ing technology and a limited non-renewable resource pool, that may be a prac-
World biomass tical assessment. On the other hand, the optimistic viewpoint is that current
production
6.9x1017 kcal/yr technology is somewhat like the cavemen who first discovered fire. Most
wanted to hide but, fortunately, there were a few brave souls who saw
the potential. History has taught us that coordinated support of a
clear vision can lead to resolution of gigantic problems.
93%
unutilized Much has been written and said about the changes required to
feed a world population of 10 billion or more within the next 25
years. However, much less focus has been placed on the
material needs of such a growing human mass. We can rea-
sonably assume that having food is only part of the needs
equation. There will also be an exponentially growing demand
for energy, transportation, housing, schools, machines, and com-
puters, among other things. Where will all the resources come
from to provide the legitimate desires of this expectant population?
Drilling more and deeper wells may provide additional hydrocarbon resources,
7% but there is a limit to the reservoirs. Progress on more efficient use of existing
utilized hydrocarbons will continue, but perhaps with diminishing returns. Nanotechnol-
ogy will allow significant miniaturization with consequent savings in materials,
but some things just can’t be that small. The key point is that resources are
being depleted and it is futile to debate “when” they will run out, instead of
looking for new paradigms to allow gradual conversion to other sources.
Switching to the use of renewable resources wherever the appropriate technol-
ogy is available is a more sustainable and environmentally responsible approach.
The vision for the use of plant/crop-based resources is optimistic. With the
appropriate research and development of new approaches, we can discover
economically viable solutions to meet the needs of a full planet. This vision
sets the direction and calls for coordinated programs to identify and implement
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
4 3the actions required to build a renewable resource base utilizing the energy
and carbon capturing systems inherent in plant systems. The challenge is sig-
nificant but the opportunity is immeasurable. Humans can be responsive to
change, and with the challenges ahead we must be.
W HAT A RE P LANT /C ROP - BASED R ESOURCES ?
Plant/crop-based (sometimes termed bio-based) resources are defined as
source material derived from a range of plant systems, primarily agricultural
crops, forestry products, and processing streams in the food, feed, and fiber
industries. An inherent assumption is that they are renewable over a short
time frame through use of annual crops and trees, perennials, and short-
rotation woody species.
While petrochemical derivatives are also originally plant based, the basic mol-
ecules are hydrocarbons. With plant/crop-based renewables, the current basic
“volume” molecules are carbohydrates, lignins, and plant oils. There is also
lower volumes of high-value molecules arising from secondary plant metabolites.
Another key difference is that hydrocarbons are fixed and extraction systems
have been developed to manipulate them into the desired building blocks. To
some extent today, plant-based renewables are also often considered as being
“fixed”—taking what the plant already contains or what is left after processing.
Recent advances in biotechnology promise to allow manipulation of plant con-
stituents, and enzyme extraction systems, that could offer new economic
opportunities for existing chemical product needs and for new types of inter-
mediates and products.
The U.S. has significant plant/crop-based resources, including forestry,
rangeland, and a highly productive agricultural system. In the past 50 years,
these plant-based resources have been largely focused toward food, feed,
and fiber production.
s
Figure 4. Plant/crop-based
Co grain
resources in the United States. Wh n
a
age
For n
eat
ybe
er
er
tto
rn
Oth
Oth
Co
So
Source: USDA, World Fact Book
Forests Pastures and rangeland Other uses Main arable crops
424 million acres
2,246 million acres
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
5T HE H YDROCARBON E CONOMY
We can look back on the latter part of the twentieth century and see tremen-
dous growth in terms of economic output, especially in the developed nations
and increasingly so in the developing countries. A major factor contributing to
this success story was the development of the hydrocarbon economy. Since
the 1920s, the extraction and utilization of fossil fuels provided the economic
and standard of living benefits that we enjoy today. Many countries have
become reliant on this source for both energy needs and raw material feed-
stocks. For example, a summary outline of energy and material flows for the
yyyyyy
,,,,,,
U.S. is demonstrated in Figure 5.
Figure 5.The flows of raw In many ways this is a remarkable system, harvesting the energy that was
materials for industrial usage
once captured by plants and subsequently trapped in fossilized layers. Exten-
in the United States.
sive research and development during the past 50 years has created signifi-
,,,,,,
yyyyyy
cant value-added processes in both
energy generation and in providing
the basic building blocks for industry.
Utilities The market economics are clearly
viable and have been driven by
,,,,,,
yyyyyy
Industry
Inexpensive human desires for the standard of
Fossil fuels
Energy generation power and living created by the products of
Buildings fuels—
source
Abundant
the system.
products
Transportation
Bio-based
Note that current inputs to this sys-
source
Chemical feedstocks Manufacturing Products tem related to bio-based sources
(mainly plant-based) are very small
and account for less than 1% in
energy and less than 5% in raw
material inputs. As a comparison, the
1996 U.S. production of corn, soybeans, and small-grain cereals for food and
feed uses amounted to 690 billion pounds. It would appear that the relative eco-
nomics for use of plant-based inputs have not yet been sufficient to drive signifi-
cant contributions as industrial feedstocks. On the other hand, the
hydrocarbon-based economy has thrived.
Although hydrocarbons continue to provide a very successful economic plat-
form, there are several issues related to their future use. There appear to be
growing environmental concerns over the use of petrochemicals. While some
of these may be valid there is, however, a much larger underlying problem.
Fossil fuels are a diminishing raw material source. The use of plant/crop-based
resources provides additional inputs that are renewable, and creates the
opportunity for an orderly transition to a more sustainable economy.
As an example of the growing need to add additional renewable resources it
is worth reviewing the energy situation. The hydrocarbon source is finite and
many experts suggest that the proven and probable reserves can sustain
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
6 5world energy consumption at current rates for another 50 to 100 years. A
potential issue is the assumption that “at current rates” equates to remaining
yyyy
,,,,
constant. Is this a reasonable assumption given a growing population and
major changes in living standards around the world?
The current per capita rates of energy consumption vary considerably around
the world. Is it not reasonable to expect that the developing nations will
,,,,
yyyy
increase their energy consumption, just as the U.S. did between 1920 and
1990? The potential problem in supply is multiplied because
kWh/Capita Energy Consumption
the developing countries tend to have large populations. For
example, if energy use in China were to increase to 4000
12000 kWh/capita (about one-third of that in the U.S. today), the
incremental energy required would be about equivalent to the
,,,,
yyyy
10000 total energy used annually in the U.S. today.
8000 This example is not intended to be a “doomsday” statement,
nor to predict the timing of fossil fuel depletion. In fact, new
developments in the efficiency of hydrocarbon use will help
,,,,
yyyy
Source: The World Fact Book, CIA, 1994
6000
offset the expanding demand. Nevertheless, there is an ulti-
mate need to supplement hydrocarbon sources such that
4000
combined inputs from all sources result in a more sustainable
industrial base.
2000
New technologies require time to develop and implement. A
0 USA France Japan Brazil Thailand China
good example is the petrochemical industry itself. In 1920,
the economics of hydrocarbon feedstocks were not as attrac-
tive as they are today. Over the last 50 years, the processes have been devel-
Figure 6. Current rates of energy
consumption per capita vary oped to fit the fossil fuel situation. How long will it take to develop
widely around the world. plant/crop-based systems to the same level of sophistication?
Now is the time for significant research and development on what renewable
sources and novel processes might be available, and for beginning to develop
selection criteria among the possible alternatives. Doing the research now
does not mean that the system must change immediately. However, at some
point in the future the economics of the hydrocarbon economy will fail: either
through higher environmental costs or simply due to escalating prices for
diminishing raw materials.
Funding the appropriate research now will allow relevant comparisons
between potential sources of energy and raw materials and provide much-
needed choices. In the medium-to-long term, alternatives such as plant/crop-
based renewable sources may be both environmentally acceptable and
economically attractive. In the shorter term, research and development may
point to certain areas where plant/crop-based renewables can begin to enter
the market for basic building-block molecules, thereby adding to the source
base and prolonging the usefulness of the valuable fossil fuel reserves.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
7T HE V ISION FOR P LANT /C ROP -B ASED R ENEWABLES IN 2020
yyy
,,,
The vision is to provide continued economic growth, healthy standards of living,
and strong national security through the development of plant/crop-based renew-
,,,
yyy
able resources that are a viable alternative to the current dependence on non-
renewable, diminishing fossil resources.
mplicit in this vision is the concept that plant-based resources will be phased
Fossil-based resources
I in as increasingly important sources of raw materials for industry. The use of
yyy
,,,
Plant-based resources
non-renewables may be extended with substitutions by plant-based renew-
ables being driven by economic and environmental factors. Waiting until a crisis
occurs and then trying to initiate major replacements is contrary to the vision.
Note that the vision for 2020 assumes fossil fuels will still contribute 90% of
yyy
,,,
the base inputs. The addition of plant-based renewables is not an “either/or”
situation, it is a necessary contribution to meet future demands. Of course,
new routes for efficient processing and utilization of these plant-derived build-
ing blocks will be required. Research on these routes must start today to allow
sufficient time for economic development, and to ensure the rational incorpora-
tion of best practices relative to potential environmental impacts.
Today 2020 2050
The directional targets for successful progress are:
Figure 7. Vision of estimated ■ To achieve at least 10% of basic chemical building blocks arising from
input proportions. plant-derived renewables by 2020, with development concepts in place by
then to achieve a further increase to 50% by 2050.
■ To establish plant-based (crop, forestry, processing) systems producing
renewable feedstocks with efficient conversion processes to allow an eco-
nomically viable and environmentally sensitive manufacturing platform for
selected products by 2020. Such a production chain will demonstrate the
economic viability and other potential benefits of an integrated, plant/crop-
based feedstock system and highlight further areas of opportunity for com-
mercial introductions to contribute to both domestic and export needs
beyond the year 2020.
■ To build collaborative partnerships among industrial stakeholders, growers,
producers, academia, and federal and state governments to develop small-
to large-scale commercial applications, revitalizing the economy in rural
regions and providing improved integration along the value-added process-
ing and manufacturing chain. The distinction between processing food, feed,
and fiber and manufacturing basic materials will begin to disappear.
Research and development projects that provide detailed goals and objectives
in support of these directional targets should receive priority for funding.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
8 7P LANT /C ROP -B ASED R ESOURCES AS F EEDSTOCKS :
C URRENT S TATUS
S ITUATION A NALYSIS
ydrocarbons have become a mainstay of modern living through provision
H of energy and building blocks for clothing, plastics, oils, paints, dyes,
pharmaceuticals, and so on. Petroleum-based plastics increased 400% between
1970 and 1990 and have gradually replaced glass, metals and even paper.
Plant/crop-based resources are not effectively used today for reasons that
may include lack of utility, poor quality, variable supply, or high cost. The
following sections address actions needed to drive and increase interest in
using plant/crop-based renewables.
U TILITY
Although the total quantity consumed is low, plant-based materials are cur-
rently used for a wide variety of chemicals, ranging from paints to adhesives to
lubricants. Soybeans have been a traditional source of vegetable oils, and
more recent genetic advances have allowed the production of specialty oils for
particular lubricant markets. Also, in recent years the use of soybean-derived
ink has become relatively common.
For some chemicals, such as ethanol, sorbitol, cellulose, citric acid, natural
rubber, most amino acids, and all proteins, plant-based systems are the
major sources.
In terms of quantities of plant material used, wood for paper and fiberboard
products is by far the largest segment.
Million tons
Inputs used per year Uses
Wood 80.9 Paper, paperboard, lignocellulose
composites
Industrial starch 3.0 Adhesives, polymers, resins
Vegetable oils 1.0 Surfactants, inks, paints, resins
Natural rubber 1.0 Tires, household goods
Wood extractives 0.9 Oils, gums
Cellulose 0.5 Textile fibers, polymers
Lignin 0.2 Adhesives, tanning, vanillin
Source: The Carbohydrate Economy, D. Morris and D. Ahmed, 1992
The majority of cases involved use plant-based material in an original molecu-
lar state. Complex molecules such as lignocellulose, vegetable oils, and rub-
ber are used as such with limited chemical modification. This is in contrast to
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
9yyy
,,,
,,,
yyy
21 billion
pounds of
the petrochemical industry, which has developed the chemistry necessary to
break down hydrocarbons into a few simple molecules (such as methane,
propylene, etc). These building blocks are then used to chemically synthesize
desired complex molecules.
,,,
yyy
corn
In a few cases, plant/crop material is broken down to provide a different basic
molecule. Examples include the expanded production of high-fructose corn
syrup and the fermentation of corn starch to produce fuel ethanol.
Processed via
These examples demonstrate that plant-derived materials do have utility, either
,,,
yyy
fermentation
with novel as native complex molecules or in some cases via modification during pro-
enzymes cessing. Additionally, the utility is not just for highly specialized molecules
(e.g., medicinal), but can encompass larger volume intermediates and products.
S UPPLY Q UALITY
yyy
,,,
AND
Plant systems are geographically dispersed and encounter diverse edaphic
0.9 billion and weather conditions, resulting in variations in supply and quality. Forest and
C2H5OH gallons of
ethanol
agricultural systems have been developed to manage such vagaries with a
resulting narrower range of variation in supply compared to natural wild vegetation.
yyy
,,,
General biomass production from plants is plentiful but its use has been lim-
ited due to the lack of economical chemical conversion technologies. Plant
biomass tends to be “structural” material, often high in lignin and hemicellu-
9 billion gallons lose, which contribute to difficulties in chemical manipulation. New develop-
blended gasoline
(1996) ments such as fast pyrolysis may allow opportunities for extraction of low
molecular weight products. Additional improvements in separations technology
would also help drive these. Sources of biomass could be fast-growing woody
Figure 8.Chemical conversion species (e.g., poplar, eucalyptus), field/range crops (e.g., selected grasses,
of starch to ethanol is difficult alfalfa), and other specially bred plant species.
and too costly. When microbial
enzymes are used, the process
Other potential sources of biomass supply are current crops grown for food or
becomes more economically
viable. This example also feed (e.g., corn, soybeans, wheat, sorghum). In every case, only a portion of
demonstrates that new possi- these crops is harvested. Typically the harvested portion is around one-half of
bilities might exist through novel the plant material available. Just for these four crops, there is an estimated
enzyme-driven processes. average of 2600 lb/acre on a dry matter basis left in the field, providing a
total of over 520 billion pounds of dry matter. While a portion of this must be
retained for soil structure and to prevent erosion, the majority could be
removed and used as feedstocks if appropriate, cost-effective handling sys-
tems and processing technology were available.
A major issue to be addressed in supply relates to the intent of the original
production and how that is to be managed. Today, trees are grown for wood
and pulp, crops are grown for food, feed, or fiber, and have not been well opti-
mized for multiple uses. Evaluations of input costs have been based on
plant/crop inputs from non-optimized (as raw materials) plant production sys-
tems, and thus carry an up-front economic penalty.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
10 9Some proponents of increased use of plant-based renewables point to the
many acres of so-called marginal land (low unit biomass production), and sug-
gest that those acres should be the source of materials for feedstocks. Mar-
ginal land is called marginal for a reason. If economic comparisons are to be
made using plant production levels from marginal land, it is difficult to envision
why such a system alone would be economically viable.
Currently low-input, low-output plant production is generally not profitable for
the farmer, does not support the rural community (via service needs), and may
not provide lower unit cost feedstock for the processor. Moreover, the output is
often variable in both quantity and quality. The ultimate products from such a
system are likely to carry high unit costs and to severely limit the economic
viability of the whole chain. Additionally, because low-output production
requires many more acres, the unit impact on the environment is often much
greater than from a more intensive system.
This is not to say that some land not well-used today
A SIMPLIFIED ANALYSIS OF HYPOTHETICAL PRODUCTION ON could not be better used, nor that some plant vari-
MARGINAL VERSUS GOOD CROPLANDS
eties will be developed to better utilize such condi-
To estimate dry matter output on marginal lands versus good lands, using corn,
let’s assume a yield of 35 bushels per acre on marginal lands. This is equivalent to tions. For major driving forces we need to consider
the typical yield historically obtained before modern agricultural practices became optimized production systems, in addition to making
widespread. If 55 percent of the crop is harvested and moisture content is 18 per-
cent, 2,922 pounds of dry matter (grain and residues) would be obtained per acre. marginal lands more productive.
On good croplands, let’s assume increased usage levels if crops are grown for
more than just food and feed. The current average of 120 bushels per acre yield There is a need to better understand the implications
might grow to 200 bushels per acre. If 55 percent of the crop is harvested and
moisture content is again 18 percent, 16,698 pounds of dry matter will be obtained. of using highly productive land as a resource for
To estimate the anticipated economic return using these yields, it is necessary to plant/crop-based renewable raw materials: either the
adjust the fertilizer, chemicals, and application levels for marginal lands for eco-
nomic feasibility. Let’s assume favorable conditions that allow using only half the
whole crop, or portions not used for food or feed pro-
typical input requirements. The resulting variable costs are: duction. This would also help address the issues of
Good land Marginal land quantity and quality variation.
Seed 22.38 22.38 same seed required
Fertilizer 43.47 21.74 use only half the amount on marginal land
Chemicals 24.63 12.31 use only half the amount The 1996 Farm Bill promoted efficient production by
Application 8.27 4.13 use only half the amount allowing changes in agricultural production decision-
Fuel 11.05 11.05 same cultivation and harvesting
Repairs 12.74 12.74 making. Farmers will grow crops based more on market
Labor 6.05 6.05 forces than previously. How will this impact the poten-
Total variable 128.59 90.40
tial for plant-based feedstocks? For example, a farmer
If we assume the grain price to be $2.60 per bushel, net income would be $391.00
per acre for good land (200 bu x $2.60=$520, minus $128.59 variable may make a decision based on the projected supply-
costs=$391.00) or $183.00 if yields remain at the average (120 bushels per acre) demand for ethanol compared to that for vegetable
level, as opposed to 60 cents per acre for marginal lands (35 bu x $2.60=$91.00,
minus $90.40 variable costs=$.60). oils! The first choice is “corn” or “soybeans,” the next
This explains why cultivating marginal land can not return a profit, whether used choice is “what variety” (if corn, then select high starch
for industrial feedstocks or food, feed, or fiber. To effect major change, we need to for ethanol or high oil for feeding), the following choice
consider optimized production systems for good lands in addition to making mar-
ginal lands more productive. is what level of input-output to use, and so on through
which field and whether to use precision application.
Successful developments toward the vision of plant/crop-based renewables
resources will extend these decisions: food or feed? feed or feedstocks? oil or
starch? fiber or sugars? pharmaceuticals or polymers? The implications of
such supply- and demand-driven decisions require more detailed investigation
than has been devoted to this subject to date.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
11C OST OF P LANT /C ROP - BASED R AW M ATERIALS T ODAY
The cost of raw materials is probably the most common objection raised
regarding the use of plant/crop-based renewables. The critics say it is not eco-
nomical to use such inputs compared to hydrocarbons. Industrial production is
driven by high-volume, low-cost raw materials. Plant materials, such as lignin
or starch, can also be high-volume, low-cost materials and could compete on
a commodity basis if the appropriate systems were developed.
The types of cost comparisons that have been done historically showed that
plant-based materials were not particularly well-suited to the economics of the
petrochemical industry, but in cases where cost was similar, the portion of
material derived from plants increased significantly:
Product Production Conventional Plant Derived Plant Derived
Million tons Cost $/lb Cost $/lb %
Furfural 0.3 0.75 0.78 97.0
Adhesives 5.0 1.65 1.40 40.0
Fatty acids 2.5 0.46 0.33 40.0
Surfactants 3.5 0.45 0.45 35.0
Acetic acid 2.3 0.33 0.35 17.5
Plasticizers 0.8 1.50 2.50 15.0
Carbon black 1.5 0.50 0.45 12.0
Detergents 12.6 1.10 1.75 11.0
Pigments 15.5 2.00 5.80 6.0
Dyes 4.5 12.00 21.00 6.0
Wall paints 7.8 0.50 1.20 3.5
Inks 3.5 2.00 2.50 3.5
Special paints 2.4 0.80 1.75 2.0
Plastics 30.0 0.50 2.00 1.8
The real issue is perhaps one of cost of conversion to “force fit” plant-derived
materials into a manufacturing system that requires a different chemical strat-
egy. In many ways the comparison is an apples-and-oranges situation. There
is a need to avoid the conflict of “either/or” and explore what opportunities can
be developed to use the best of both sources of raw materials.
Plant/crop-based renewables are really not alternative sources. They are addi-
tional sources of materials for use as industrial feedstocks. The “alternative” is
in process issues.
Cost limitations appear not to concern raw material cost, but rather cost asso-
ciated with processing. This is really an “available technology” issue. With fur-
ther development of new thermal, chemical, and biological processes, there
are opportunities to expand the use of plant-based renewables in economically
viable systems.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
12 11P LANT /C ROP -B ASED R ESOURCES AS F EEDSTOCKS :
L OOKING A HEAD
A M ATRIX FOR A NALYSIS OF F UTURE D EVELOPMENTS
lant-based inputs may take several forms (wood, cellulose, lignin, starch,
P amino acids, etc.), and may be sourced from different places (biomass,
crop residues, dedicated crops, crop processing by-products, etc.). In some
Figure 9. This matrix creates a
structure to begin evaluating respects, this diversity is not a good fit for an industrial system that has been
opportunities and priority areas developed to break down hydrocarbons into a set of simple molecules and
for research and development. then to rebuild these into desired products. It is more fruitful to consider the
Each cell in the matrix should be
development of novel processing streams, rather than just multiple sources for
analyzed for technology needs
the existing processing stream. Both approaches may be viable, but require
and economic viability.
analysis within the appropriate context.
Novel
molecules
By evaluating the possible inputs, available
technology, product-type outputs, and com-
Processing systems
Bio- petitive sourcing within each matrix cell, new
processes
opportunities may be more accurately quanti-
Modified fied. Such assessments would highlight priori-
chemistry ties for commercial development within
Current
particular sets of actual (or assumed) condi-
chemistry tions. Additionally, cross-cell comparisons
may allow research to be focused on the
Year areas of greatest need, based on highest
2020
potential return for any given set of conditions.
Waste &
by-products
Another dimension that may be more easily
Existing Technology understood using this matrix is that of time.
Plant input
crop parts
front today Clearly, genetically modified plants that pro-
Dedicated
duce novel products of high value relative
crops to the consumable end-product will be eco-
nomically attractive and may offer additional
Modified
genetics benefits. However, focusing on this segment
alone may result in missing shorter-term
opportunities because those conditions are probably a more long-term proposi-
The “technology front”
tion. It is useful to view the matrix in terms of “where the technology front is
estimates where we are today,
demonstrates the concept of today,” which may help sort out short-, medium-, and long-term research and
simultaneous developments development needs:
within several cells (sets of input-
output conditions), and shows Completing assessments for each of the cells will help provide answers to
progress toward the future. where research should be focused. For example, while progress today seems
to be a “front” across the segments, it is relevant to ask who is coordinating
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
13this effort along the front and across disciplines and projects? What are the
directional targets and criteria for success? What mechanism allows the cap-
ture of synergy among projects along the technology front?
Is it better to focus on one aspect in any particular time-frame, or even attempt
to “leap-frog” certain sets of conditions? We need to better understand the
technical options and social and economic implications of various approaches.
Answers to such questions will help focus limited research funds into poten-
tially higher-return projects, and allow the technology to be implemented in a
more timely manner.
In the next section, each of the cells (condition sets) will be examined briefly
for current fit and future potential fit with the vision outlined for plant/crop-
Novel
molecules based renewable resources. The comments provided are examples of the sta-
Bio- tus and possibilities, and are not intended to be prescriptive.
processes
Modified
chemistry S EGMENT P OTENTIALS
Current
chemistry
1. WASTE S TREAMS AND B Y- PRODUCTS
Waste &
by-products
Today this is an opportunistic segment but could become more important as
Existing new processing technologies develop.
crop parts
Technology
Dedicated
crops
front today A) Current Chemistry
Modified The forestry industry has developed the use of by-products to a significant
genetics
extent: e.g., pulping liquors converted into lignosulfonate surfactants, dimethyl-
sulfoxide, or bark used as a source of tannin. The crop milling and crushing
Figure 10. industry has developed many uses for by-products of commodity processing:
e.g., furfural from oats, starch-derived adhesives, specialty cottonseed oils, cit-
rates and amino acids from wet mills, etc. However, many food processing
operations, such as vegetables and fruits, have not developed any particular
uses that fit the existing system, and often discharge starch and sugars into
the environment.
Use of plant by-products appears to be an opportunistic situation based on
inherent molecules rather than any good fit with existing chemical manufactur-
ing. Extraction and sale of inherent products may be viewed as a tactical
method of reducing the cost of doing business, more so than a strategic move
toward the use of plant-based resources.
B) Modified Chemistry
Woody plant material and several crop processing streams have a high con-
tent of lignocellulose and other carbohydrate materials. While the hydrocarbon
industry has developed the capability to convert complex material into very
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
14 13discrete chemicals, the technologies needed to achieve this with plant-derived
materials need to be further developed. Development of inexpensive plant-
derived fermentation sugars is on the horizon. Advances in organometallic
chemistry directed at converting carbohydrates into value-added chemicals are
examples of the evolving new technologies that may allow expanded use of
plant-based materials.
Modified chemistry has potential and may allow economic returns from plant-
derived waste streams.
C) Bio-processing
Fermentation using microbes results in the production of certain molecules in
a complex “soup” which may then be separated into desirable components.
Bio-transformations are typically one-step processes using microbes, cells, or
cell-free enzyme systems and provide opportunities to improve the utilization
of waste streams and by-products. With improvements in separation technol-
ogy, bio-processes are likely to be more widely used to harvest waste streams.
Novel
D) Novel Molecules
molecules It is unlikely that this segment will become an important reality since “novel”
Bio-
processes
molecules will be created due to some demand (and high value). Reliance on
Modified production from waste streams would not be the best source of materials for
chemistry such products.
Current
chemistry
2. E XISTING C ROP PARTS
Waste &
by-products Perhaps the largest short-term opportunity to expand the use of plant-based
Existing materials.
crop parts
Technology
Dedicated
crops
front today A) Current Chemistry
Modified Overall the chemical industry has not found plant-derived material to be of
genetics
high economic value, and there are limited case-by-case uses. As discussed
previously, the petrochemical industry evolved to utilize hydrocarbons, not car-
Figure 11. bohydrates or other bio-based molecules. Thus, we have what we have and
further expectations should not be raised for this segment.
B) Modified Chemistry
If the plant-derived material is structural biomass then certain constituents,
such as lignin and cellulosics, predominate. New techniques such as inte-
grated combustion or organometallic chemistry may provide opportunities to
better utilize this type of source. In addition to forestry sources, crop residues
are a 520-billion-pound source of biomass which is not utilized today.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
15yyyyy
,,,,,
,,,,,
yyyyy
L
ea
ves
Processing (306,000 tons)
High-protein
feed
An example of the use of crop parts in
an integrated manner is the Minnesota
Agri-Power project. Some 680,000
tons of alfalfa are converted into feed
m
Alfalfa
with an additional net energy output.
ea
(680,000 tons)
St
t em
S
s Combustion Steam
Gasifier Turbine Turbine Net 75 MW Alternative processing routes allowed
parts of an existing source to be used
more effectively.
Figure 12. The Minnesota As new chemical technology develops there may be additional significant
Agri-Power project uses up to
opportunities to use plant parts that are rich in a particular component, e.g.,
680,000 tons of alfalfa crop
sugar or starch. Plant starches come in different forms such as starches from
residues to produce 75 megawatts
of electricity per day. rice, potatoes, corn, and wheat. All have different properties and offer different
inherent uses. More needs to be understood about the potential for such com-
ponents combined with modified chemistry.
However, a key issue in this segment relates to value of developing modified
chemistry versus the segment (see below) of bio-processing of crop parts.
Perhaps a combination of bio-processing, new chemical processes, and
advanced separation technology may provide significant opportunities.
C) Bio-processing
Again the source of plant parts for bio-processing is large and diverse, from
structural biomass to specific plant constituents. There are several potential
advantages in favor of bio-processing:
Traditional Recent advances
Advantages Disadvantages include:
• Mild reaction conditions • Dilute solutions • Improved continuous
• High reaction specificity • Low unit yield • process
• Lower reaction energy barrier • Feedback inhibition • Advanced separations
• Coupled sequential reactions • Separation/purification • technology
• Range of energy sources • costs • Genetic modification:
• Fewer toxic by-products • – Enzyme copy number
• – Energy source
• Cell-free enzyme chemistry
Probably the most successful use of bio-processing of corn parts is in the
enzymatic conversion of corn-derived glucose into high fructose corn syrup. In
1995, the production of 20 billion pounds of high fructose corn syrup used 34
billion pounds of corn.
Recent developments in this input-output segment hold significant promise for
shorter-term enhancement of the use of plant-derived materials. One example
is the process, developed through the collaboration of four Department of
Energy laboratories, to make succinic acid via fermentation of glucose from
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
16 15corn. When separated, the succinate can be used to make several chemicals
including butanediol, tetrahydrofuran, and pyrrolidinones. These intermediates
can then be utilized to manufacture a wide assortment of products in a market
segment that, today, uses one billion pounds of materials valued at $1.3 bil-
lion. This process is currently undergoing pilot-plant development.
In addition to the immediate commercial utility, this example is interesting
because it demonstrates the potential for new process development that may
occur when different scientific disciplines (from microbial genetics to advanced
separation chemistry) are brought together to provide novel solutions. This
may be an excellent model for further short-term advances in using plant-
based renewables as chemical feedstocks.
D) Novel Molecules
While plant-derived inputs are relatively fixed in this segment (biomass, pro-
tein, oil, starch, etc.) the possibility to genetically modify the microbes used, or
to produce specific enzymes, opens up some potential for the creation of novel
molecules. Such activities are limited to small niche markets today, because
the infrastructure for large-scale manufacturing is not in place. However, as
the market demand for new products with particular molecular characteristics
increases, then economic growth could occur from this input-output set.
Integrated technical and economic research is required along the product
development chain, starting with definition of the desired product—desired
characteristics—molecular structures—intermediates—enzyme technology—
protein/genetic engineering—best source of plant inputs—optimization of pro-
Novel
molecules duction of selected inputs in the crop parts of choice, and so on.
Bio-
processes
Modified As in the case of succinate, this approach can be viewed as an alternative
chemistry processing route rather than just another source of feedstock inputs.
Current
chemistry
3. D EDICATED C ROPS
Waste &
by-products
A medium-term opportunity to expand the use of plant-based materials through
Existing improvement in the source of inputs.
crop parts
Technology
Dedicated
crops
front today A) Current Chemistry
Modified Since the chemical industry has generally not found crop parts to be of high
genetics
economic value it seems unlikely that dedicated crops would be any more
attractive. It may be argued that dedicated crops could lower the cost of inputs
Figure 13. but, as mentioned previously, the real limitations may be in technology rather
than input costs per se.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
17B) Modified Chemistry
The same situation exists for this input-output segment as for plant parts as
inputs, with the added potential that dedicated crops may allow additional effi-
ciencies. For example, it may be possible to more precisely align the crop type
with the needs of the modified chemical process. Is biomass the best input?
Or should the crop be higher or lower in particular constituents (oils, starches,
proteins)? Do these help or hinder the modified process?
Another potential advantage of dedicated crops might be in relation to the
logistics of supply. Depending on how the modified process is implemented,
and the scale of the operations, there could be a need to draw input supplies
from a surrounding area. Whether this is a current crop or use of new grass
types in rangeland, the question of available supply and transport must be
addressed. This is a parallel development situation with modified processing
and plant supplies providing mutual support for growth.
Although several uses may exist in any one region, there may be develop-
ments of particular types in certain areas. The technology will need to fit geo-
graphic and edaphic regions. These operations may be repeated around the
country as appropriate to the fit.
This alignment of new process facilities and supply would include opportunities
for the economies of rural regions.
This concept of processing and production being close to supply is not
unusual in industry. Petrochemical facilities are close to oil or coal supplies
(indigenous or import), the orange juice processing industry is centered in the
citrus-growing regions of Florida, and so on. Having plant-based inputs grown
in one region and transported to another carries a large cost of transport
penalty. One reason that plant-based materials have not been well integrated
into traditional chemical processing may be because the hydrocarbon process-
ing facilities tend not to be located in areas of high crop or forest production.
C) Bio-processing
Relative to inputs this segment is similar to that for modified chemistry. The
difference is in how the material is processed into intermediates and/or final
products. The centers of dedicated crop supply could be based around fer-
mentation facilities just as easily as chemical facilities.
As technology develops to allow the implementation of such processing cen-
ters, there will be a need for research to determine the best alignment of
inputs with the process. For example, will the dedicated crop be a single crop
for a single fermentation reaction? Or will different bio-processes use different
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
18 17Novel
parts of the crop (e.g. grain for one use and crop residue for another) in the
molecules same facility? Or will dual dedicated crops be required (e.g. a lignin bio-
Bio-
processes
process that requires some sugar inputs as an energy supply)? Optimizing
Modified such alignments will be important to the economy of the operation and for the
chemistry
development of the region around the facility.
Current
chemistry
4. M ODIFIED G ENETICS
Waste &
by-products A medium- to long-term opportunity to expand the use of plant-based materials
Existing in specific ways and for specific uses. Some of these will provide outcomes
crop parts
Technology that we can hardly imagine today.
Dedicated front today
crops
Modified Whether it’s called the carbohydrate economy or something else, there will be
genetics
a whole new industrial platform based on the bio-engineering of plant con-
stituents to provide alternative renewable resources.
Figure 14.
A) Current Chemistry
Genetic modification of plant-based inputs could likely be achieved to provide
some inputs to the existing hydrocarbon processing system. However, modi-
fied plant molecules may be too valuable to degrade in a hydrocarbon system.
In other words, the input technology will be able to leapfrog the processing
technology. Either more complex molecules can be made directly and inserted
further up the manufacturing chain, or new processing routes will be much
more efficient at using the modified inputs. Benefits of the dual change will be
seen in both the economy and in environmental issues.
B) Modified Chemistry
Clearly, there will be benefits from developing new process routes that opti-
mize the type of plant/crop-input and the process. Parallel research needs to
be directed at these possibilities.
In what time frame should these process research efforts be made? This can
best be answered by assessing where the genetic manipulation technology is
today, and how long it will be before such changes are expected in commercial
situations. An overview of this situation is provided in the following section on
the impact of biotechnology.
C) Bio-processing
This input-output segment is similar to that for modified chemistry. The addi-
tional factor is that microbes or enzymes or both may also be genetically
altered to provide enhanced processing capabilities. There appears to be very
large longer-term potential for biological engineering, where optimization can
be created between input materials and the bio-process itself.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
19In some cases, the desired molecular building blocks may be partially synthe-
sized in the plant material and “finished off” by bio-transformations or highly
specific biological/chemical processes. The processes will be created to take
account of the best method(s) for the highest efficiency, provide for optimized
economics, and maximize environmental benefits.
At some point during the next 50-70 years, petrochemical processing for gen-
eral high-volume molecules will begin to look somewhat sluggish, inflexible,
and expensive. Research and development will be required to justify continu-
ing to use fossil fuels for specialized uses in order to gain maximum value
from the remaining limited resource.
D) Novel Molecules
In just the past 20 years, plastics have grown into a huge industry, replacing
glass, porcelain, wood, and metal for many everyday uses. The marketplace
continues to change, driven by the desires and expectations of consumers.
Materials science continues to make significant advances, marketers continue
to design novel consumer goods, and expectations rise. Who can predict what
the next “plastic” will be? Yet we know there will be one.
The possibilities for novel molecules to be the bases of new industrial plat-
forms are many. The concept of marrying physical and chemical science with
the ability to biologically engineer material inputs generates a new horizon.
Plant-based renewable resources will be a major part of that future. Plants are
highly effective factories for capturing and converting freely available solar
energy. Metabolic engineering to channel that resource into desirable building
blocks to support the infrastructure of society appears to be a desirable
approach. It’s an area where the technology front should be advanced to
explore the boundaries of possibility.
Someday, we may have solar energy collectors that contain self-replicating
chloroplasts, with integrated solid-phase enzyme nanoreactors—all built into
the computer controlled vehicular surfaces that in the twentieth century were
called roads. In the meantime, plant-derived materials may work out just fine.
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20 19T HE P OTENTIAL I MPACT OF B IOTECHNOLOGY
yyyyy
,,,,,,,,,
yyyy
The impact of any new area of technology may be assessed by:
■ exploring the speed of change and/or the rate of introduction in recent time,
■ measuring the level of interest and funding by public companies,
■ evaluating patent activity and associations, and
,,,,,
yyyyy
■ looking into the development pipeline to see what is making successful
,,,,
yyyy
progress.
Transgenic Plant Evaluations: Modified Constituents Proportion of Plants Types Evaluated, 1996
,,,,,
yyyyy
25 Number of plants tested
yyyy
,,,,
Number of participating organizations Soybean
Corn
20
15
,,,,,yyyy
yyyyy,,,,
10
Tomato Other
5
Cotton
167 Total field tests Potato
0 1994 1995 1996
Figure 15. Much activity is n the early 1990s, many people were very skeptical that biotechnology
underway in transgenic modifica-
tion of plant constituents.
I would make much difference in the crop world. By 1996, the commercial
success of transgenic crops had been clearly demonstrated. These first suc-
cesses relate to new crop protection approaches. While it is important to pro-
tect plant production from the ravages of pests and diseases, it is also
important, and relevant to the vision, to understand the possibilities for modifi-
cation of plant constituents.
Due to regulatory requirements, transgenic field test records are kept by the Ani-
mal and Plant Health Inspection Service. Such evaluations are for events that
have been demonstrated in the laboratory and are now moving into the pipeline
for development testing. Selecting the records that relate only to transgenic
modification of plant constituents shows that considerable activity is underway.
The data show that several organizations are involved and that work is already
underway in several crops. Among the organizations involved, the number of
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21tests and types of modifications range from one per organization to dozens of
field transgenic tests by the major players such as DuPont, Monsanto, and
Pioneer Hi-Bred.
Some of the events being evaluated are related to alteration of constituents to
improve nutritional quality, some are for processing characteristics, and others
are for industrial or pharmaceutical uses. The types of transgenic modifications
already being evaluated include:
■ Carbohydrate (sugars, starch, solids) alterations,
■ Oil and fatty acid modification,
■ Amino acid level enhancement,
■ Protein type manipulation,
■ Fiber characteristic modification,
■ Antibody production,
■ Industrial enzyme production,
■ Secondary compound manipulation (sterols, carotenoids, etc.), and
■ New polymer production.
We can reasonably conclude that transgenic technology progress is significant
and is moving rapidly. A new door has been opened on the opportunity for
plant-based materials to provide useful sources of both molecular building
blocks and more complex molecules for manufacturing industries. A specific
example of this is the plant-based production of polymers for plastic manufac-
turing. Three genes from the bacterium Alcaligenes eutrophus have been
inserted into the lipid synthesis pathway of plants with the result that polyhy-
droxybutyrate was synthesized in concentrations of up to 14%. Expression of
this biodegradable thermoplastic is being developed further in soybeans, cot-
ton, and rapeseed.
Conventional plant breeding has raised yields threefold over the past 50 years,
and the selection process in those crops was for characteristics that had a
good fit with food, feed, and fiber uses. Advanced plant breeding with the aid
of genomic maps and transgenic techniques will provide an opportunity to fur-
ther increase food and feed production with a simultaneous potential to pro-
vide plant-based materials as feedstocks for many uses.
Biotechnology already has a revolutionary impact on plant-based materials.
However, use of biotechnology to alter plants to fit a hydrocarbon economy
may not be the best approach. There needs to be an improved understanding
of what factors along the industrial chain need to be aligned in order to take
maximum advantage of future transgenic plant-based renewable resources.
P L A N T / C R O P - B A S E D R E N E WA B L E R E S O U R C E S 2 0 2 0
22 21You can also read
